The Master, Multiplied | Kiki-Jiki, Mirror Breaker | Izzet Chemister (and one other card)

Cards

({4} magic symbol) ({U} magic symbol) ({U} magic symbol) ({R} magic symbol) available the first turn, with ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) each extra turn available.

Cast
Walk the Aeons by paying ({4} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing you to take an extra turn after this one.
Activate
Kiki-Jiki by tapping it, creating a token copy of
Izzet Chemister.
Activate the
Izzet Chemister token's first ability by paying ({R} magic symbol) and tapping it, exiling
Walk the Aeons from your graveyard.
At the beginning of your end step,
Kiki-Jiki triggers, but you cannot sacrifice the
Izzet Chemister token due to
The Master.
On your next turn, activate the
Izzet Chemister token's last ability by paying ({1} magic symbol) ({R} magic symbol) , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost.
Resolve that spell, causing you to take an extra turn after this one.
Repeat from step 2.

This combo has been estimated to be Ruthless (Bracket 4+).